There were dramatic scenes in Westminster today when Nick Clegg confirmed the death of Lords reform and said he would whip his MPs to oppose boundary changes.

The deputy prime minister looked angry and tired as he announced to the press that the centrepieces of the coalition's constitutional reforms would die off due to a breakdown of relations among governing party MPs.

"Unfortunately the prime minister has confirmed to me that an insufficient number of his MPs have been persuaded to support the [Lords reform] bill," Clegg said.

"I can confirm today we do not intend to proceed with the bill in this parliament.

"My party has held to [the coalition] contract even when it meant voting for things that we found difficult," he added.

"But the Conservative party is not honouring the agreement to Lords reform and as a result part of our contract has been broken.

"I cannot permit a situation where Tory rebels pick the part of the contract they like. Coalition works on mutual respect, it is a reciprocal arrangement.

"When, in due course, parliament votes on boundary changes for the 2015 election I will be instructing my party to oppose them."

In a press conference which felt like the beginning of the end for the coalition, Clegg argued that the tit-for-tat refusals on Lords reform and boundaries were not the result of political bickering, but of constitutional principle.

"If you cut the number of MPs without enhancing the legitimacy and effectiveness of the Lords all you've done is weaken parliament as a whole [and] strengthen the executive," he said.

Clegg also revealed that he made an offer to hold a referendum on Lords reform at the time of the next general election but the offer was not accepted.

The deputy prime minister vowed to continue on in government, despite the obvious implications of the announcement for the coalition.

"We will continue to anchor this government firmly in the centre ground," he said.

Tories rebelled en masse against Lords reform, with many of them brutally attacking the deputy prime minster in the Commons. The move offended Lib Dems, who were relying on a strong presence in a Lords elected by proportional representation to maintain themselves after what is expected to be a bruising general election.

The Conservatives, who are relying on the boundary review to boost their number of MPs in 2015, will almost certainly not be able to get the legislation to pass without Lib Dem support.